The best description I can give is to suck on a piece of soggy cardboard or chew a sheet of paper. I found a bottle of my homebrew that was probably 8-10 years old and of course I had to try it. It was crystal clear, nicely carbonated but tasted absolutely like a wet cardboard box smells.

along, similar lines...What do folks consider best practice for oxygenation prior to fermentation. I've read that an O2 tank and stone deliver the most optimal ppm. But recently with the ramp up costs of a keezer build and going all grain it may be some time before I can get that expenditure approved by the finance officer (brewmistress). By the way, the Brewmistress would like to express her gratitude for the advice of never off-gassing in her presence.

along, similar lines...What do folks consider best practice for oxygenation prior to fermentation. I've read that an O2 tank and stone deliver the most optimal ppm. But recently with the ramp up costs of a keezer build and going all grain it may be some time before I can get that expenditure approved by the finance officer (brewmistress). By the way, the Brewmistress would like to express her gratitude for the advice of never off-gassing in her presence.

Some use tanks and stones. You can use a mixstir or shake also. I prefer agitation and then a big pitch of yeast.

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The first principle is that you must not fool yourself, and you are the easiest person to fool. -Richard P. Feynman

Laws are spider-webs, which catch the little flies, but cannot hold the big ones. -Anacharsis

Oxidation flavors can take many different forms. Wet cardboard and paper are some of the more obvious and offensive ones, but it won't always present that way. In general, you'll notice a dullness of flavor, where what was once bright, fresh and clean will seem muted, dusty, and bland. It can make a beer seem more caramelly sweet, or fruity, depending on what was in the beer before it was oxidized. Some take on sherry or madeira notes. I think melanoidins and maillard products tend to get those sherry notes, while acids tend to get estery. I also tend to notice the finish getting harsher and seemingly more bitter. The color can fade or at least darken in hue. It might start getting cloudy or showing flakes suspended. There are a lot of chemical compounds in beer, and all of them will oxidize. Each reacts differently. So the art is in deducing that it has happened when it shows up in so many different forms and intensities. It's not like flipping a switch; there is a matter of degrees. For the average beer, I'd say it usually shows up as dull and more caramelly, before it starts getting obviously stale.

along, similar lines...What do folks consider best practice for oxygenation prior to fermentation. I've read that an O2 tank and stone deliver the most optimal ppm. But recently with the ramp up costs of a keezer build and going all grain it may be some time before I can get that expenditure approved by the finance officer (brewmistress). By the way, the Brewmistress would like to express her gratitude for the advice of never off-gassing in her presence.

Some use tanks and stones. You can use a mixstir or shake also. I prefer agitation and then a big pitch of yeast.

Same. I shake the hell out of my fermenters for 4-5 minutes after filling them when I pitch the yeast. Never had an issue. My last batch was OG: 1.062 and finished at 1.010.

I personally use the O2 bottle and stone. Just about every homebrew store has a kit, but you have to get the O2 bottle at your local hardware store because they can't be shipped. If you go this route, you need to be careful not to over do it. You can have too much of a good thing, promote too much yeast growth, and end up with less-than-clean beer. Just follow the directions and you will be fine.

There are a couple of different kinds. Mine comes with a regulator, the stone on the end of a stainless rod, and a length of clear hose. If I recall correctly, i think that was about $30. The O2 bottle from Home Depot is about $10. The directions come with the regulator/stone kit.

If it is quick oxidation this is what I get as well. The longer it develops the more "sherry wine" like it gets. The wet cardboard is a decent analogy as well.

And I'm glad Gordon also mentioned the weird caramel taste that oxidized beers have. That's something I perceive, too, that you don't see get mentioned much.

Yeah, just go to Germany and have some Ayinger or Spaten or Paulaner or whatever and then come back to the States and buy some dusty bottles of the same off the shelf. That will make anyone understand the caramel/sweet aspect of oxidation.